1. Field of the Invention
The present invention relates to an LED (Light-Emitting Diode) stabilizing light source device suitable for measurement of light propagation characteristics of an optical fiber.
2. Description of the Related Art
When the ambient temperature of an LED serving as a light-emitting element changes, output light therefrom also changes. Therefore, conventionally, the ambient temperature of the LED is measured using a heat-sensitive element such as a thermistor, and an output from a drive circuit for driving the LED is controlled in accordance with the sensed temperature, thus stabilizing the output light from the LED.
In the above conventional system, however, it generally takes several tens of minutes until the output light is stabilized after a power switch is turned on.
Since, furthermore, the temperature characteristics of LEDs are generally different, each LED requires a thermistor suitable to the LED. However, the temperature characteristics of LEDs and thermistors are generally not the same, thus an error will occur between the temperature characteristics. Therefore, it is required to compensate for the error to control the driving of the LEDs with high precision. However, this is troublesome and lowers the operability of the device.